Steam turbine plant

Abstract

A steam turbine plant of one embodiment includes a boiler configured to change water into steam, a high pressure turbine including a turbine or turbines connected to each other in series, and having a first inlet to supply the steam from the boiler, an extraction port located at a downstream of the first inlet, a second inlet to supply the steam extracted from the extraction port and located at a downstream of the extraction port, and an exhaust port located at a downstream of the second inlet, the high pressure turbine being configured to be driven by the steam supplied from the first and second inlets, an extraction steam heater configured to heat the steam extracted from the extraction port and to supply the heated steam to the second inlet, a reheater configured to heat the steam exhausted from the exhaust port, and a reheat turbine configured to be driven by the steam from the reheater.

The invention claimed is: 
     
       1. A steam turbine plant comprising:
 a boiler configured to change water into steam; 
 a high pressure turbine including a turbine or turbines connected to each other in series, and having a first inlet configured to supply the steam from the boiler, an extraction port located downstream of the first inlet, a second inlet configured to supply the steam extracted from the extraction port and located downstream of the extraction port, and an exhaust port located downstream of the second inlet, the high pressure turbine being configured to be driven by the steam supplied from the first and second inlets, and the steam from the first inlet and the steam from the second inlet being merged in the high pressure turbine and exhausted from the exhaust port; 
 an extraction steam heater configured to heat the steam extracted from the extraction port and to supply the heated steam to the second inlet; 
 a reheater configured to heat the steam exhausted from the exhaust port; and 
 a reheat turbine configured to be driven by the steam from the reheater. 
 
     
     
       2. The plant of  claim 1 , further comprising a solar energy collector configured to collect solar heat,
 wherein the heater, the extraction steam heater, and the reheater are configured to heat the water or the steam to be heated, by the solar heat. 
 
     
     
       3. The plant of  claim 2 , wherein
 the solar energy collector is a trough condensing solar energy collector. 
 
     
     
       4. The plant of  claim 1  wherein
 a difference between an inlet steam temperature at the first inlet and a saturation temperature under an inlet steam pressure at the first inlet is 100° C. or less. 
 
     
     
       5. The plant of  claim 1 , wherein
 inlet steam at the first inlet has a pressure of 20 ata or more and a temperature of 420° C. or less. 
 
     
     
       6. The plant of  claim 1 , further comprising:
 a first steam valve configured to adjust a flow rate of the steam supplied to the second inlet or to stop a circulation of the steam supplied to the second inlet. 
 
     
     
       7. The plant of  claim 1 , further comprising:
 a second steam valve configured to adjust a flow rate of the steam extracted from the extraction port or to stop a circulation of the steam extracted from the extraction port. 
 
     
     
       8. The plant of  claim 1 , wherein
 a turbine other than a most downstream turbine among all turbines of the steam turbine plant is configured to operate such that the steam circulating inside the turbine is maintained as dry steam, wherein all turbines of the steam turbine plant include the turbine or the turbines of the high pressure turbine and a turbine or turbines of the reheat turbine.